This invention relates generally to medical imaging systems and, more particularly, to methods and systems for filtering scan data in medical imaging systems.
In computed tomography (CT) systems, an X-ray source emits a fan-shaped beam toward an object such as a patient or a piece of luggage. The beam is attenuated by the object. The attenuated beam impinges upon an array of radiation detectors. The intensity of the attenuated beam radiation received at the detector array depends upon the attenuation of the X-ray beam by the object. Each detector element of the detector array produces a separate electrical signal that is indicative of the attenuated beam received by each detector element. The electrical signals are transmitted to a data processing system for analysis, which results in the formation of a plurality of images.
In cardiac CT systems, directional streaks lined up with ventricles, aorta and a vertebra are visible in the generated images. These artifacts are more pronounced when a contrast agent is used. Further, the existence of streaking artifacts may cause a noise-induced banding artifact in the images, preventing doctors from using scans with a low dose of X-ray radiation.